// This source file is part of the polarphp.org open source project
//
// Copyright (c) 2017 - 2019 polarphp software foundation
// Copyright (c) 2017 - 2019 zzu_softboy <zzu_softboy@163.com>
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://polarphp.org/LICENSE.txt for license information
// See https://polarphp.org/CONTRIBUTORS.txt for the list of polarphp project authors
//
// Created by polarboy on 2018/06/03.

#include "polarphp/basic/adt/Hashing.h"
#include "gtest/gtest.h"
#include "polarphp/global/DataTypes.h"
#include "polarphp/basic/adt/StringRef.h"
#include <deque>
#include <list>
#include <map>
#include <vector>

namespace polar {
namespace basic {

// Helper for test code to print hash codes.
void PrintTo(const HashCode &code, std::ostream *os)
{
   *os << static_cast<size_t>(code);
}

// Fake an object that is recognized as hashable data to test super large
// objects.
struct LargeTestInteger { uint64_t arr[8]; };

struct NonPOD
{
   uint64_t x, y;
   NonPOD(uint64_t x, uint64_t y) : x(x), y(y) {}
   friend HashCode hash_value(const NonPOD &obj)
   {
      return hash_combine(obj.x, obj.y);
   }
};

namespace hashing {
namespace internal {
template <> struct is_hashable_data<LargeTestInteger> : std::true_type {};
} // namespace detail
} // namespace hashing

} // utils
} // polar

namespace {

enum TestEnumeration
{
   TE_Foo = 42,
   TE_Bar = 43
};

using polar::basic::HashCode;
using polar::basic::hash_value;
using polar::basic::hash_combine_range;
using polar::basic::hash_combine;
using polar::basic::NonPOD;
using polar::basic::StringRef;
using polar::basic::LargeTestInteger;

} // anonymous namespace

TEST(HashingTest, testHashValueBasicTest)
{
   int x = 42, y = 43, c = 'x';
   void *p = nullptr;
   uint64_t i = 71;
   const unsigned ci = 71;
   volatile int vi = 71;
   const volatile int cvi = 71;
   uintptr_t addr = reinterpret_cast<uintptr_t>(&y);
   EXPECT_EQ(hash_value(42), hash_value(x));
   EXPECT_EQ(hash_value(42), hash_value(TE_Foo));
   EXPECT_NE(hash_value(42), hash_value(y));
   EXPECT_NE(hash_value(42), hash_value(TE_Bar));
   EXPECT_NE(hash_value(42), hash_value(p));
   EXPECT_EQ(hash_value(71), hash_value(i));
   EXPECT_EQ(hash_value(71), hash_value(ci));
   EXPECT_EQ(hash_value(71), hash_value(vi));
   EXPECT_EQ(hash_value(71), hash_value(cvi));
   EXPECT_EQ(hash_value(c), hash_value('x'));
   EXPECT_EQ(hash_value('4'), hash_value('0' + 4));
   EXPECT_EQ(hash_value(addr), hash_value(&y));
}

TEST(HashingTest, testHashValueStdPair)
{
   EXPECT_EQ(hash_combine(42, 43), hash_value(std::make_pair(42, 43)));
   EXPECT_NE(hash_combine(43, 42), hash_value(std::make_pair(42, 43)));
   EXPECT_NE(hash_combine(42, 43), hash_value(std::make_pair(42ull, 43ull)));
   EXPECT_NE(hash_combine(42, 43), hash_value(std::make_pair(42, 43ull)));
   EXPECT_NE(hash_combine(42, 43), hash_value(std::make_pair(42ull, 43)));

   // Note that pairs are implicitly flattened to a direct sequence of data and
   // hashed efficiently as a consequence.
   EXPECT_EQ(hash_combine(42, 43, 44),
             hash_value(std::make_pair(42, std::make_pair(43, 44))));
   EXPECT_EQ(hash_value(std::make_pair(42, std::make_pair(43, 44))),
             hash_value(std::make_pair(std::make_pair(42, 43), 44)));

   // Ensure that pairs which have padding bytes *inside* them don't get treated
   // this way.
   EXPECT_EQ(hash_combine('0', hash_combine(1ull, '2')),
             hash_value(std::make_pair('0', std::make_pair(1ull, '2'))));

   // Ensure that non-POD pairs don't explode the traits used.
   NonPOD obj1(1, 2), obj2(3, 4), obj3(5, 6);
   EXPECT_EQ(hash_combine(obj1, hash_combine(obj2, obj3)),
             hash_value(std::make_pair(obj1, std::make_pair(obj2, obj3))));
}

TEST(HashingTest, testHashValueStdString)
{
   std::string s = "Hello World!";
   EXPECT_EQ(hash_combine_range(s.c_str(), s.c_str() + s.size()), hash_value(s));
   EXPECT_EQ(hash_combine_range(s.c_str(), s.c_str() + s.size() - 1),
             hash_value(s.substr(0, s.size() - 1)));
   EXPECT_EQ(hash_combine_range(s.c_str() + 1, s.c_str() + s.size() - 1),
             hash_value(s.substr(1, s.size() - 2)));

   std::wstring ws = L"Hello Wide World!";
   EXPECT_EQ(hash_combine_range(ws.c_str(), ws.c_str() + ws.size()),
             hash_value(ws));
   EXPECT_EQ(hash_combine_range(ws.c_str(), ws.c_str() + ws.size() - 1),
             hash_value(ws.substr(0, ws.size() - 1)));
   EXPECT_EQ(hash_combine_range(ws.c_str() + 1, ws.c_str() + ws.size() - 1),
             hash_value(ws.substr(1, ws.size() - 2)));
}

namespace {

template <typename T, size_t N> T *begin(T (&arr)[N]) { return arr; }
template <typename T, size_t N> T *end(T (&arr)[N]) { return arr + N; }

// Provide a dummy, hashable type designed for easy verification: its hash is
// the same as its value.
struct HashableDummy { size_t value; };
HashCode hash_value(HashableDummy dummy) { return dummy.value; }

} // anonymous namespace

TEST(HashingTest, testHashCombineRangeBasicTest)
{
   // Leave this uninitialized in the hope that valgrind will catch bad reads.
   int dummy;
   HashCode dummy_hash = hash_combine_range(&dummy, &dummy);
   EXPECT_NE(HashCode(0), dummy_hash);

   const int arr1[] = { 1, 2, 3 };
   HashCode arr1_hash = hash_combine_range(begin(arr1), end(arr1));
   EXPECT_NE(dummy_hash, arr1_hash);
   EXPECT_EQ(arr1_hash, hash_combine_range(begin(arr1), end(arr1)));

   const std::vector<int> vec(begin(arr1), end(arr1));
   EXPECT_EQ(arr1_hash, hash_combine_range(vec.begin(), vec.end()));

   const std::list<int> list(begin(arr1), end(arr1));
   EXPECT_EQ(arr1_hash, hash_combine_range(list.begin(), list.end()));

   const std::deque<int> deque(begin(arr1), end(arr1));
   EXPECT_EQ(arr1_hash, hash_combine_range(deque.begin(), deque.end()));

   const int arr2[] = { 3, 2, 1 };
   HashCode arr2_hash = hash_combine_range(begin(arr2), end(arr2));
   EXPECT_NE(dummy_hash, arr2_hash);
   EXPECT_NE(arr1_hash, arr2_hash);

   const int arr3[] = { 1, 1, 2, 3 };
   HashCode arr3_hash = hash_combine_range(begin(arr3), end(arr3));
   EXPECT_NE(dummy_hash, arr3_hash);
   EXPECT_NE(arr1_hash, arr3_hash);

   const int arr4[] = { 1, 2, 3, 3 };
   HashCode arr4_hash = hash_combine_range(begin(arr4), end(arr4));
   EXPECT_NE(dummy_hash, arr4_hash);
   EXPECT_NE(arr1_hash, arr4_hash);

   const size_t arr5[] = { 1, 2, 3 };
   const HashableDummy d_arr5[] = { {1}, {2}, {3} };
   HashCode arr5_hash = hash_combine_range(begin(arr5), end(arr5));
   HashCode d_arr5_hash = hash_combine_range(begin(d_arr5), end(d_arr5));
   EXPECT_EQ(arr5_hash, d_arr5_hash);
}

TEST(HashingTest, testHashCombineRangeLengthDiff)
{
   // Test that as only the length varies, we compute different hash codes for
   // sequences.
   std::map<size_t, size_t> code_to_size;
   std::vector<char> all_one_c(256, '\xff');
   for (unsigned Idx = 1, Size = all_one_c.size(); Idx < Size; ++Idx) {
      HashCode code = hash_combine_range(&all_one_c[0], &all_one_c[0] + Idx);
      std::map<size_t, size_t>::iterator
            I = code_to_size.insert(std::make_pair(code, Idx)).first;
      EXPECT_EQ(Idx, I->second);
   }
   code_to_size.clear();
   std::vector<char> all_zero_c(256, '\0');
   for (unsigned Idx = 1, Size = all_zero_c.size(); Idx < Size; ++Idx) {
      HashCode code = hash_combine_range(&all_zero_c[0], &all_zero_c[0] + Idx);
      std::map<size_t, size_t>::iterator
            I = code_to_size.insert(std::make_pair(code, Idx)).first;
      EXPECT_EQ(Idx, I->second);
   }
   code_to_size.clear();
   std::vector<unsigned> all_one_int(512, -1);
   for (unsigned Idx = 1, Size = all_one_int.size(); Idx < Size; ++Idx) {
      HashCode code = hash_combine_range(&all_one_int[0], &all_one_int[0] + Idx);
      std::map<size_t, size_t>::iterator
            I = code_to_size.insert(std::make_pair(code, Idx)).first;
      EXPECT_EQ(Idx, I->second);
   }
   code_to_size.clear();
   std::vector<unsigned> all_zero_int(512, 0);
   for (unsigned Idx = 1, Size = all_zero_int.size(); Idx < Size; ++Idx) {
      HashCode code = hash_combine_range(&all_zero_int[0], &all_zero_int[0] + Idx);
      std::map<size_t, size_t>::iterator
            I = code_to_size.insert(std::make_pair(code, Idx)).first;
      EXPECT_EQ(Idx, I->second);
   }
}

TEST(HashingTest, testHashCombineRangeGoldenTest)
{
   struct { const char *s; uint64_t hash; } golden_data[] = {
#if SIZE_MAX == UINT64_MAX || SIZE_MAX == UINT32_MAX
   { "a",                                0xaeb6f9d5517c61f8ULL },
   { "ab",                               0x7ab1edb96be496b4ULL },
   { "abc",                              0xe38e60bf19c71a3fULL },
   { "abcde",                            0xd24461a66de97f6eULL },
   { "abcdefgh",                         0x4ef872ec411dec9dULL },
   { "abcdefghijklm",                    0xe8a865539f4eadfeULL },
   { "abcdefghijklmnopqrstu",            0x261cdf85faaf4e79ULL },
   { "abcdefghijklmnopqrstuvwxyzabcdef", 0x43ba70e4198e3b2aULL },
   { "abcdefghijklmnopqrstuvwxyzabcdef"
      "abcdefghijklmnopqrstuvwxyzghijkl"
      "abcdefghijklmnopqrstuvwxyzmnopqr"
      "abcdefghijklmnopqrstuvwxyzstuvwx"
      "abcdefghijklmnopqrstuvwxyzyzabcd", 0xdcd57fb2afdf72beULL },
   { "a",                                0xaeb6f9d5517c61f8ULL },
   { "aa",                               0xf2b3b69a9736a1ebULL },
   { "aaa",                              0xf752eb6f07b1cafeULL },
   { "aaaaa",                            0x812bd21e1236954cULL },
   { "aaaaaaaa",                         0xff07a2cff08ac587ULL },
   { "aaaaaaaaaaaaa",                    0x84ac949d54d704ecULL },
   { "aaaaaaaaaaaaaaaaaaaaa",            0xcb2c8fb6be8f5648ULL },
   { "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", 0xcc40ab7f164091b6ULL },
   { "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
      "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
      "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
      "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
      "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", 0xc58e174c1e78ffe9ULL },
   { "z",                                0x1ba160d7e8f8785cULL },
   { "zz",                               0x2c5c03172f1285d7ULL },
   { "zzz",                              0x9d2c4f4b507a2ac3ULL },
   { "zzzzz",                            0x0f03b9031735693aULL },
   { "zzzzzzzz",                         0xe674147c8582c08eULL },
   { "zzzzzzzzzzzzz",                    0x3162d9fa6938db83ULL },
   { "zzzzzzzzzzzzzzzzzzzzz",            0x37b9a549e013620cULL },
   { "zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz", 0x8921470aff885016ULL },
   { "zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz"
      "zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz"
      "zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz"
      "zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz"
      "zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz", 0xf60fdcd9beb08441ULL },
   { "a",                                0xaeb6f9d5517c61f8ULL },
   { "ab",                               0x7ab1edb96be496b4ULL },
   { "aba",                              0x3edb049950884d0aULL },
   { "ababa",                            0x8f2de9e73a97714bULL },
   { "abababab",                         0xee14a29ddf0ce54cULL },
   { "ababababababa",                    0x38b3ddaada2d52b4ULL },
   { "ababababababababababa",            0xd3665364219f2b85ULL },
   { "abababababababababababababababab", 0xa75cd6afbf1bc972ULL },
   { "abababababababababababababababab"
      "abababababababababababababababab"
      "abababababababababababababababab"
      "abababababababababababababababab"
      "abababababababababababababababab", 0x840192d129f7a22bULL }
#else
#error This test only supports 64-bit and 32-bit systems.
#endif
   };
   for (unsigned i = 0; i < sizeof(golden_data)/sizeof(*golden_data); ++i) {
      StringRef str = golden_data[i].s;
      HashCode hash = hash_combine_range(str.begin(), str.end());
#if 0 // Enable this to generate paste-able text for the above structure.
      std::string member_str = "\"" + str.str() + "\",";
      fprintf(stderr, " { %-35s 0x%016llxULL },\n",
              member_str.c_str(), static_cast<uint64_t>(hash));
#endif
      EXPECT_EQ(static_cast<size_t>(golden_data[i].hash),
                static_cast<size_t>(hash));
   }
}

TEST(HashingTest, testHashCombineBasicTest) {
   // Hashing a sequence of homogenous types matches range hashing.
   const int i1 = 42, i2 = 43, i3 = 123, i4 = 999, i5 = 0, i6 = 79;
   const int arr1[] = { i1, i2, i3, i4, i5, i6 };
   EXPECT_EQ(hash_combine_range(arr1, arr1 + 1), hash_combine(i1));
   EXPECT_EQ(hash_combine_range(arr1, arr1 + 2), hash_combine(i1, i2));
   EXPECT_EQ(hash_combine_range(arr1, arr1 + 3), hash_combine(i1, i2, i3));
   EXPECT_EQ(hash_combine_range(arr1, arr1 + 4), hash_combine(i1, i2, i3, i4));
   EXPECT_EQ(hash_combine_range(arr1, arr1 + 5),
             hash_combine(i1, i2, i3, i4, i5));
   EXPECT_EQ(hash_combine_range(arr1, arr1 + 6),
             hash_combine(i1, i2, i3, i4, i5, i6));

   // Hashing a sequence of heterogeneous types which *happen* to all produce the
   // same data for hashing produces the same as a range-based hash of the
   // fundamental values.
   const size_t s1 = 1024, s2 = 8888, s3 = 9000000;
   const HashableDummy d1 = { 1024 }, d2 = { 8888 }, d3 = { 9000000 };
   const size_t arr2[] = { s1, s2, s3 };
   EXPECT_EQ(hash_combine_range(begin(arr2), end(arr2)),
             hash_combine(s1, s2, s3));
   EXPECT_EQ(hash_combine(s1, s2, s3), hash_combine(s1, s2, d3));
   EXPECT_EQ(hash_combine(s1, s2, s3), hash_combine(s1, d2, s3));
   EXPECT_EQ(hash_combine(s1, s2, s3), hash_combine(d1, s2, s3));
   EXPECT_EQ(hash_combine(s1, s2, s3), hash_combine(d1, d2, s3));
   EXPECT_EQ(hash_combine(s1, s2, s3), hash_combine(d1, d2, d3));

   // Permuting values causes hashes to change.
   EXPECT_NE(hash_combine(i1, i1, i1), hash_combine(i1, i1, i2));
   EXPECT_NE(hash_combine(i1, i1, i1), hash_combine(i1, i2, i1));
   EXPECT_NE(hash_combine(i1, i1, i1), hash_combine(i2, i1, i1));
   EXPECT_NE(hash_combine(i1, i1, i1), hash_combine(i2, i2, i1));
   EXPECT_NE(hash_combine(i1, i1, i1), hash_combine(i2, i2, i2));
   EXPECT_NE(hash_combine(i2, i1, i1), hash_combine(i1, i1, i2));
   EXPECT_NE(hash_combine(i1, i1, i2), hash_combine(i1, i2, i1));
   EXPECT_NE(hash_combine(i1, i2, i1), hash_combine(i2, i1, i1));

   // Changing type w/o changing value causes hashes to change.
   EXPECT_NE(hash_combine(i1, i2, i3), hash_combine((char)i1, i2, i3));
   EXPECT_NE(hash_combine(i1, i2, i3), hash_combine(i1, (char)i2, i3));
   EXPECT_NE(hash_combine(i1, i2, i3), hash_combine(i1, i2, (char)i3));

   // This is array of uint64, but it should have the exact same byte pattern as
   // an array of LargeTestIntegers.
   const uint64_t bigarr[] = {
      0xaaaaaaaaababababULL, 0xacacacacbcbcbcbcULL, 0xccddeeffeeddccbbULL,
      0xdeadbeafdeadbeefULL, 0xfefefefededededeULL, 0xafafafafededededULL,
      0xffffeeeeddddccccULL, 0xaaaacbcbffffababULL,
      0xaaaaaaaaababababULL, 0xacacacacbcbcbcbcULL, 0xccddeeffeeddccbbULL,
      0xdeadbeafdeadbeefULL, 0xfefefefededededeULL, 0xafafafafededededULL,
      0xffffeeeeddddccccULL, 0xaaaacbcbffffababULL,
      0xaaaaaaaaababababULL, 0xacacacacbcbcbcbcULL, 0xccddeeffeeddccbbULL,
      0xdeadbeafdeadbeefULL, 0xfefefefededededeULL, 0xafafafafededededULL,
      0xffffeeeeddddccccULL, 0xaaaacbcbffffababULL
   };
   // Hash a preposterously large integer, both aligned with the buffer and
   // misaligned.
   const LargeTestInteger li = { {
                                    0xaaaaaaaaababababULL, 0xacacacacbcbcbcbcULL, 0xccddeeffeeddccbbULL,
                                    0xdeadbeafdeadbeefULL, 0xfefefefededededeULL, 0xafafafafededededULL,
                                    0xffffeeeeddddccccULL, 0xaaaacbcbffffababULL
                                 } };
   // Rotate the storage from 'li'.
   const LargeTestInteger l2 = { {
                                    0xacacacacbcbcbcbcULL, 0xccddeeffeeddccbbULL, 0xdeadbeafdeadbeefULL,
                                    0xfefefefededededeULL, 0xafafafafededededULL, 0xffffeeeeddddccccULL,
                                    0xaaaacbcbffffababULL, 0xaaaaaaaaababababULL
                                 } };
   const LargeTestInteger l3 = { {
                                    0xccddeeffeeddccbbULL, 0xdeadbeafdeadbeefULL, 0xfefefefededededeULL,
                                    0xafafafafededededULL, 0xffffeeeeddddccccULL, 0xaaaacbcbffffababULL,
                                    0xaaaaaaaaababababULL, 0xacacacacbcbcbcbcULL
                                 } };
   EXPECT_EQ(hash_combine_range(begin(bigarr), end(bigarr)),
             hash_combine(li, li, li));
   EXPECT_EQ(hash_combine_range(bigarr, bigarr + 9),
             hash_combine(bigarr[0], l2));
   EXPECT_EQ(hash_combine_range(bigarr, bigarr + 10),
             hash_combine(bigarr[0], bigarr[1], l3));
   EXPECT_EQ(hash_combine_range(bigarr, bigarr + 17),
             hash_combine(li, bigarr[0], l2));
   EXPECT_EQ(hash_combine_range(bigarr, bigarr + 18),
             hash_combine(li, bigarr[0], bigarr[1], l3));
   EXPECT_EQ(hash_combine_range(bigarr, bigarr + 18),
             hash_combine(bigarr[0], l2, bigarr[9], l3));
   EXPECT_EQ(hash_combine_range(bigarr, bigarr + 20),
             hash_combine(bigarr[0], l2, bigarr[9], l3, bigarr[18], bigarr[19]));
}

TEST(HashingTest, testHashCombineArgs18)
{
   // This tests that we can pass in up to 18 args.
#define CHECK_SAME(...)                                                        \
   EXPECT_EQ(hash_combine(__VA_ARGS__), hash_combine(__VA_ARGS__))
   CHECK_SAME(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18);
   CHECK_SAME(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17);
   CHECK_SAME(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16);
   CHECK_SAME(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15);
   CHECK_SAME(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14);
   CHECK_SAME(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13);
   CHECK_SAME(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12);
   CHECK_SAME(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11);
   CHECK_SAME(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
   CHECK_SAME(1, 2, 3, 4, 5, 6, 7, 8, 9);
   CHECK_SAME(1, 2, 3, 4, 5, 6, 7, 8);
   CHECK_SAME(1, 2, 3, 4, 5, 6, 7);
   CHECK_SAME(1, 2, 3, 4, 5, 6);
   CHECK_SAME(1, 2, 3, 4, 5);
   CHECK_SAME(1, 2, 3, 4);
   CHECK_SAME(1, 2, 3);
   CHECK_SAME(1, 2);
   CHECK_SAME(1);
#undef CHECK_SAME
}
